Re: [PATCH 2/3] [kexec-tools] Pass vmcoreinfo's address and size

Simon Horman
2007-10-17T02:33:20Z

On Wed, Aug 22, 2007 at 09:13:39PM +0900, Ken'ichi Ohmichi wrote:
>
> [2/3] [kexec-tools] Pass vmcoreinfo's address and size
> The patch is for kexec-tools-testing-20070330.
> (http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/)
> kexec command gets the address and size of the vmcoreinfo data from
> /sys/kernel/vmcoreinfo, and passes them to the second kernel through
> ELF header of /proc/vmcore. When the second kernel is booting, the
> kernel gets them from the ELF header and creates vmcoreinfo's PT_NOTE
> segment into /proc/vmcore.

Sorry for the long delay, I completely missed this patch.

The kexec-tools change seems ok to me. What is the status of
the kernel portion of the change? Do you still want the
kexec-tools portion applied?

>
> Thanks
> Ken'ichi Ohmichi
>
> ---
> Signed-off-by: Dan Aloni <da-x@monatomic.org>
> Signed-off-by: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
>
> ---
> diff -rpuN backup/kexec-tools-testing-20070330/kexec/crashdump-elf.c kexec-tools/kexec/crashdump-elf.c
> --- backup/kexec-tools-testing-20070330/kexec/crashdump-elf.c 2007-03-30 13:34:36.000000000 +0900
> +++ kexec-tools/kexec/crashdump-elf.c 2007-08-03 14:45:47.000000000 +0900
> @@ -36,6 +36,8 @@ int FUNC(struct kexec_info *info,
> char *bufp;
> long int nr_cpus = 0;
> uint64_t notes_addr, notes_len;
> + uint64_t vmcoreinfo_addr, vmcoreinfo_len;
> + int has_vmcoreinfo = 0;
> int (*get_note_info)(int cpu, uint64_t *addr, uint64_t *len);
>
> if (xen_present())
> @@ -47,7 +49,11 @@ int FUNC(struct kexec_info *info,
> return -1;
> }
>
> - sz = sizeof(EHDR) + nr_cpus * sizeof(PHDR) + ranges * sizeof(PHDR);
> + if (get_kernel_vmcoreinfo(&vmcoreinfo_addr, &vmcoreinfo_len) == 0) {
> + has_vmcoreinfo = 1;
> + }
> +
> + sz = sizeof(EHDR) + (nr_cpus + has_vmcoreinfo) * sizeof(PHDR) + ranges * sizeof(PHDR);
>
> /*
> * Certain architectures such as x86_64 and ia64 require a separate
> @@ -148,6 +154,21 @@ int FUNC(struct kexec_info *info,
> dfprintf_phdr(stdout, "Elf header", phdr);
> }
>
> + if (has_vmcoreinfo) {
> + phdr = (PHDR *) bufp;
> + bufp += sizeof(PHDR);
> + phdr->p_type = PT_NOTE;
> + phdr->p_flags = 0;
> + phdr->p_offset = phdr->p_paddr = vmcoreinfo_addr;
> + phdr->p_vaddr = 0;
> + phdr->p_filesz = phdr->p_memsz = vmcoreinfo_len;
> + /* Do we need any alignment of segments? */
> + phdr->p_align = 0;
> +
> + (elf->e_phnum)++;
> + dfprintf_phdr(stdout, "vmcoreinfo header", phdr);
> + }
> +
> /* Setup an PT_LOAD type program header for the region where
> * Kernel is mapped if info->kern_size is non-zero.
> */
> diff -rpuN backup/kexec-tools-testing-20070330/kexec/crashdump.c kexec-tools/kexec/crashdump.c
> --- backup/kexec-tools-testing-20070330/kexec/crashdump.c 2007-03-30 13:34:36.000000000 +0900
> +++ kexec-tools/kexec/crashdump.c 2007-08-03 14:45:05.000000000 +0900
> @@ -108,3 +108,35 @@ int get_crash_notes_per_cpu(int cpu, uin
>
> return 0;
> }
> +
> +/* Returns the physical address of start of crash notes buffer for a kernel. */
> +int get_kernel_vmcoreinfo(uint64_t *addr, uint64_t *len)
> +{
> + char kdump_info[PATH_MAX];
> + char line[MAX_LINE];
> + int count;
> + FILE *fp;
> + unsigned long long temp, temp2;
> +
> + *addr = 0;
> + *len = 0;
> +
> + sprintf(kdump_info, "/sys/kernel/vmcoreinfo");
> + fp = fopen(kdump_info, "r");
> + if (!fp) {
> + die("Could not open \"%s\": %s\n", kdump_info,
> + strerror(errno));
> + return -1;
> + }
> +
> + if (!fgets(line, sizeof(line), fp))
> + die("Cannot parse %s: %s\n", kdump_info, strerror(errno));
> + count = sscanf(line, "%Lx %Lx", &temp, &temp2);
> + if (count != 2)
> + die("Cannot parse %s: %s\n", kdump_info, strerror(errno));
> +
> + *addr = (uint64_t) temp;
> + *len = (uint64_t) temp2;
> +
> + return 0;
> +}
> diff -rpuN backup/kexec-tools-testing-20070330/kexec/crashdump.h kexec-tools/kexec/crashdump.h
> --- backup/kexec-tools-testing-20070330/kexec/crashdump.h 2007-03-30 13:34:36.000000000 +0900
> +++ kexec-tools/kexec/crashdump.h 2007-08-03 14:45:05.000000000 +0900
> @@ -2,6 +2,7 @@
> #define CRASHDUMP_H
>
> extern int get_crash_notes_per_cpu(int cpu, uint64_t *addr, uint64_t *len);
> +extern int get_kernel_vmcoreinfo(uint64_t *addr, uint64_t *len);
>
> /* Need to find a better way to determine per cpu notes section size. */
> #define MAX_NOTE_BYTES 1024
> _
>
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